The present invention relates to improvements in apparatus for connecting a service line at a right angle to a buried main.
In the provision of utility services to residential areas, and the like, it has been common to use conduits for gas mains formed from polyethylene, and the like. These gas mains are normally installed parallel to and under the center of a road or alley. The individual connections to the main by residences, and the like extend horizontally from and a right angle to the main. Since these mains carry natural gas, their installation specifications are prescribed by various governmental agencies. For example, the United States Department of Transportation prescribes specifications such as the depth at which the gas mains must be buried in the earth.
In many situations, this depth is very important. For example, in some areas, an increase in depth can involve a substantial increase in installation costs. This can be due to the existence of a layer of rock. Also due to the fact that these gas mains extend for miles in many cases, the increased cost due to increases in depth can be substantial. Therefore, in some areas, it is of primary importance to maintain the depth of the main at a minimum while complying with the specifications set by the various government agencies.
In the provision of service connections to a main in environments such as residential developments, it is desirable and quite common to use a fitting to form a right angle connection to the main. Many of these fittings can be installed while gas is present in the main and without disturbing service of customers already connected to the main. These fittings typically have means for attaching to the exterior of the main and means for forming a port in the wall of the main. Typical prior art arrangements for making a right angle service line connection are disclosed in the following U.S. Patents:
Patent No. Patentee Issue Date ______________________________________ RE26,447 McMurray et al Aug. 27, 1968 936,618 Ford Oct. 12, 1909 3,045,512 Risley et al Jul. 24, 1962 3,094,137 Burke Jun. 18, 1963 3,252,475 Jones May 24, 1966 3,307,435 Floren Mar. 7, 1967 3,342,088 Smith Sept. 19, 1967 3,411,527 Nielsen Nov. 19, 1968 3,460,553 Leopold et al Aug. 12, 1969 3,554,217 Ehrens Jan 12, 1971 3,561,298 Graffenreid et al Feb. 9, 1971 3,620,245 Finney Oct. 21, 1969 3,756,261 Minchhoff Nov. 16, 1971 ______________________________________
Typical prior art arrangements for making parallel-extending service line connections are disclosed in the following Patents:
Patent No. Patentee Issue Date ______________________________________ 3,131,712 Risley et al May 5, 1964 3,142,205 Hulslander July 28, 1964 3,302,493 Hulslander et al February 7, 1967 3,580,269 Ehrens et al May 25, 1971 ______________________________________
Although the above-mentioned prior art devices can be used to attach a service line to a main, they are not entirely satisfactory under all conditions or service. For example, many specifications for installing gas lines not only require that the gas main be buried below a set minimum depth, but also require that all service lines and their fittings be located below this minimum depth. Thus, the use of any fittings which extend above the main or connect service lines at a position extending above the main will cause the main to be buried deeper than the set minimum. In many cases, this requires that the entire length of the main be buried deeper by the height of the vertical extension of the fitting.
Therefore, according to the present invention, an improved apparatus for attaching a service line at a right angle with respect to a gas main is provided which does not extend vertically above the main when installed and which requires a minimal amount of installation space in an access trench perpendicular to the gas main.
More specifically, according to the present invention, an apparatus for connection to a gas main is provided comprising a fitting with one end shaped to be fixed to the exterior wall of a gas main. The fitting has first and second through bores extending transverse to the length of the gas main. The bores are positioned to be axially spaced along the length of the gas main and radially extending therefrom when the fitting is fixed to the main. The first through bore is provided with means for connecting a service line. The second through bore is connected to the first by a port. The second through bore is provided with internal threads for engaging an externally-threaded tapping means. The tapping means has a cutting head at one end and is axially manipulated in the bore to remove a coupon from the wall of the main to connect the gas main to the service line. The tapping means can be backed off and a plug placed in the end of the second bore to seal the same.